It is common now for patients to use personal health devices, for example to measure their weight or calculate their blood pressure. The results of the measurements can be used for different purposes. The measurement data is in the first place intended to provide the patient with health information. This information can also be exchanged with the patient's health service provider. If this is done remotely, the health provider can give feedback remotely, which saves time for both parties. This can offer an efficient and effective way of providing health care. The remote delivery of healthcare services can be regarded as the field of “tele-health”.
Within the domain of tele-health, measurement devices play an important role since they should provide objective information on physical (or physiological) conditions of the human body. This measurement data serves in the first place an informative purpose, for the person taking the measurements. The health data can however also be relevant for health care providers to make a diagnosis of a patient's health status. An increasing number of services, such as remote patient management, and elderly and fitness services make use of a tele-health architecture in which the measurement devices are connected to remote backend servers. Health care providers use this architecture to remotely access the measurement data and help the patients. Continua (see http://www.continuaalliance.org/) is a standardization body for personal tele-health and well being. It standardizes protocols between measurement devices, gateway (application hosting) devices and online healthcare/wellness services.
There exists the problem that healthcare measurement data obtained from patient measurement devices is not always of satisfactory quality and that remote (IT systems of) healthcare professionals have no practical and effective means to influence the quality. Related to the above problem is the question how in remote patient monitoring and tele-health applications the health care provider can help the patient and make a diagnosis without having any knowledge of quality/reliability of the measurement taken (for example, the circumstances and the conditions in which the measurement is taken).
Currently, the health care provider cannot estimate objectively how well the measurement has been performed, not even on the basis of the patient's information or experience. Typically, the person performing the measurement has received limited or no instruction on how to use the measurement device. However, healthcare providers require guaranteed sufficient quality of the measurement data, which is only the case if the measurement is taken under predefined circumstances and conditions which makes the data more reliable for diagnosis. The Continua alliance does not prescribe the quality of the data. However, it could provide the means to be able to transfer the quality and context of the data. This can be done by supporting quality and context metadata in its data models and protocols. Recent research on health data quality indication (see Ton van Deursen, Paul Koster, Milan Petkovi•, Hedaquin, “A reputation-based health data quality indicator”, 3rd International Workshop on Security and Trust Management, ESORICS 2007, Dreseden, Germany, 2007) proposes a system design which indicates the quality of health information based on ratings and reputation.